Table 5

Relation between length of longest episode of oliguria during an ICU day at risk (patient
day without a diagnosis of RIFLE I[Cr]) and AKI-Cr in the next day considering only
data gathered during the first three days of ICU admission

Longest duration of oliguria

Days with AKI-Cr

next day

Days with no AKI-Cr

next day

Sens.

Spec.

PPV

NPV

LR

P

RR of AKI-Cr

None

5

238

≥1 hr

18

175

0.78

0.57

0.09

0.98

1.9

< 0.001

4.5

≥2 hr

15

130

0.68

0.69

0.10

0.98

2.2

< 0.001

4.3

≥3 hr

13

91

0.56

0.78

0.13

0.97

2.6

< 0.001

4.2

≥4 hr

12

71

0.52

0.83

0.14

0.97

3.0

< 0.001

4.6

≥5 hr

7

59

0.30

0.85

0.11

0.96

2.1

0.06

2.5

≥6 hr

5

40

0.22

0.90

0.11

0.95

2.2

0.08

2.4

≥12 hr

4

8

0.17

0.98

0.33

0.96

9.0

0.002

7.4

Receiver-operator characteristic area under the curve for this comparison = 0.72 (0.61-0.83).
P-values refer to Fisher's exact test for presence or absence of stated degree of oliguria
and AKI outcome.